The transformation of germ cells into primordial follicles in the human fetus, then into the follicles of the ovary, represents an important and relatively little understood process. Although microscopic descriptions of the changes in the number of oogonia are available, the actual factors which may regulate cell growth, angiogenesis, apoptosis and pattern formation are unclear. The broad long-term objectives of this proposal are (1) to clarify the role of peptide growth factors as signals/agents for growth and differentiation in human fetal ovaries and (2) to understand how peptide growth factors may contribute to abnormalities in adults ovaries. The research proposed for this application is intended to accomplish these goals: . Specific Aim 1. Quantitative analysis of mRNA for growth factors and their receptors during the process of human fetal oogenesis. . Specific Aim 2. Localization by immunohistochemistry and in situ hybridization of growth factors and their receptors in human fetal ovarian development. . Specific Aim 3. To investigate the gene expression of growth factors and their receptors and to investigate apoptosis in chromosomally abnormal fetal ovaries. . Specific Aim 4. Morphological analysis of development of oogonia and surrounding cells in fetal ovaries.